Plastic shot shell wad

ABSTRACT

A unitary plastic wad structure for use with a shotshell, the wad including a shot cup portion and an obturating cup portion both of cylindrical configuration, and a plurality of plastic strips interconnect opposite circumferential portions of the shot and obturating cups to cushion a shot charge positioned in the shot cup when the wad is fired from a gun. The cushioning strips, when subjected to compressive forces generated by firing the shotshell, flex outwardly and against the shell tube wall and subsequently, the barrel bore wall to provide controlled cushioning of the shot charge.

atent States Hubbard 1March 13, 1973 [s 1 PLASTIC snor SHELL WAD Primary Examiner-Robert F. Stahl [75] inventor: Charles L. Hubbard, East Alton, lll. WW R Motsko' H Samuel Kwser and William W. Jones [73] Assignee: Olin Corporation 22 Filed: March 12, 1971 [57] ABSTRACT Appl. No.: 123,536

[52] U.S. Cl. ..l02/95, 102/42 C [51] Int. Cl ..F42b 7/08 [58] Field of Search ...l02/42, 42 C, 95

[56] References Cited UNITED STATES PATENTS 3,469,527 9/1969 Pace ..1o2/42 c 3,262,392 7/1966 Becker et al ..l02/42 C A unitary plastic wad structure for use with a shotshell, the wad including a shot cup portion and an obturating cup portion both of cylindrical configuration, and a plurality of plastic strips interconnect opposite circumferential portions of the shot and obturating cups to cushion a shot charge positioned in the shot cup when the wad is fired from a gun. The cushioning strips, when subjected to compressive forces generated by firing the shotshell, flex outwardly and against the shell tube wall and subsequently, the barrel bore wall to providecontrolled cushioning of the shot charge.

10 Claims, 6 Drawing Figures PATENTEUHARI 3l973 FIG- 1 FIG 2 FIG -6 INVENTORI CHARLES L. HUBBARD ATTORNEY PLASTIC SHOT SHELL WAD This invention concerns a unitary plastic wad structure for use with a cartridge, such as a shotshell, which wad structure includes a projectile cup portion, an obturating cup portion, and a cushioning portion interposed between and interconnecting the two cup portions. The cushioning portion is designed to provide controlled collapse and cushioning when the wad is fired from a gun so as to improve both internal and external ballistics of a charge of projectiles positioned in the projectile cup portion thereby providing improved patterns for the projectiles.

It is known in the prior art to provide plastic wad structures for use in shotshells to house the shot charge, obturate combustion gases, and cushion the shot charge when the loaded wad is fired from a gun. The prior art wad structures have been formed both as a unitary member and as a composite made from a number of components. U.S. Pats. Nos. 3,285,174 to V. C. Moehlman et al., issued Nov. 15, 1966; and 3,298,313 to R. W. Comcrford, issued Jan. 17, 1967, are typical examples of prior art unitary wad structures. U.S. Patents Nos. 3,270,669 to D. N. Atkins et al., issued Sept. 6, 1966; and 3,394,654 to H. Hazaski, issued July 30, 1968 are typical examples of prior art composite wad structures.

The use of plastic wad structures has proven useful in improving internal and external ballistics of a charge of shot pellets disposed in the shot pocket or cup. This ballistics improvement has resulted in improved shot patterns. Unitary wad structures are preferred over composite wad structures because of increased loading capabilities, ease of adapting such wads to automatic loading procedures, and reusability of fired wads. However, the prior art composite wad structures have exhibited superior pattern performance when compared to the unitary wads, such superior patterns being on the order of about percent more pellets being within a proscribed circle at a given range.

The unitary wad structure of this invention is designed to improve internal and external shot ballistic sufficiently to produce shot patterns which equal or exceed the shot patterns produced by the prior art composite wad structures. To achieve this improvement in pattern performance, the wad structure of this invention provides greater cushioning of the shot charge when the wad is fired from a shot shell, and as the shot charge travels down the gun barrel. In order to provide such improved cushioning, the wad structure is provided with a cushioning and filler wad portion having a plurality of legs providing circumferential support for the shot pocket and shot charge disposed therein. The legs are radially reinforced by the shell tube when the wad is in the shotshell, and by the gun barrel bore wall when the wad is traveling through the gun barrel. The circumferential support tends to maintain the shot column in a cylindrical form rather than tending to push through as is characteristic of the flexing center support type wads of the prior art. Furthermore, the bearing area providing radial reinforcement of the cushioning wad legs increases as the legs flex outwardly to provide increased rigidity as the pressure rises and acceleration increases. This radial reinforcement prevents complete collapse of the legs and provides a shock absorbing action to the shot from the pressure of the powder gases throughout the firing cycle. The

shock absorbing action provides for uniformity of ignition, reduced shot deformation, and rigid nesting of pellets thus improving pattern performance.

It is, therefore, an object of this invention to provide a unitary plastic wad structure for use in shotshells and the like which produces improvement in internal and external ballistics of a fired shot column to improve shot patterns.

It is further object of this invention to provide a wad structure of the character described having a cushioning or filler portion which collapses by flexing radially outwardly to provide a cushioning of the shot column when the wad is fired.

It is yet another object of this invention to provide a wad structure of the character described wherein collapse of the cushioning portion is resisted increasingly as the degree of collapse increases to protect the shot column from receiving high impact forces generated when the wad is fired.

These and other objects and advantages of the invention will become more readily apparent from the following detailed description of a preferred embodiment of the invention when taken in conjunction with the accompanying drawings, in which:

FIG. 1 is a side perspective view of a preferred embodiment of the unitary wad structure of this invention having a cushioning or filler section with three legs supporting symmetrically spaced circumferential portions of the shot cup;

FIG. 2 is a vertical section view of the wad structure of FIG. 1',

FIG. 3 is a horizontal sectional view of the wad structure taken along line 3-3 of FIG. 2;

FIG. 4 is a vertical sectional view of a shotshell showing how the wad structure of FIG. 1 is loaded therein;

FIG. 5 is a sectional view of the shotshell of FIG. 4 shown loaded into'a firearm and as it appears shortly after being fired; and

FIG. 6 is a sectional view of the wad structure showing the action of the cushioning portion as the wad passes through the barrel bore of the firearm.

Referring now to FIGS. 1-3, there is shown a preferred embodiment of a unitary wad structure formed in accordance with this invention from injection molded polyethylene plastic, or the like. The wad structure 2 includes a projectile pocket portion 4, a filler or cushioning portion 6, and an obturating portion 8. The projectile pocket 4 is shaped like a cup and includes a cylindrical plastic side wall 10, a transverse bottom wall 12 closing off the bottom of the side wall 10, and an open mouth end 14. The side wall 10 may be slitted to form petals if desired in accordance with con ventional practice. The cushioning portion 6 includes three plastic legs 16 of similar configuration. The legs 16 are symmetrically and equally angularly spaced about the circumference of the projectile cup 4 to provide equally distributed support for the circumferential periphery of the projectile cup 4. It is noted that the central portion of the projectile cup 4 is free of support in the cushioning area 6. The interior wall of each of the legs 16 is dished out, as at 18 so as to weaken the legs 16 and thus form a hinge on each of the legs 16. The hinges on the legs 16 are formed so that when the wad 2 is axially compressed, the legs 16 will flex outwardly in the direction of thearrows 20, each leg 16 flexing in an equal amount for a given compressive force. It is further noted that FlGS. l, 2 and 3 show that the outer wall of each of the legs 16 is substantially coextensive with and of the same arcuate shape as the cylindrical side wall part of the transverse walls 17 and 22 throughout the entire length of the legs 16. Thus when the wad 2 is compressed longitudinally, the cushioning portion 6 will radially expand due to the flexing action of the legs 16 about their hinges 18. The obturating portion 8 of the wad includes a transverse wall 22 of circular configuration which is formed integrally with the legs 16, and which is also integral with a cylindrical plastic skirt 24 extending longitudinally from the circumferential periphery of the wall 22. The skirt 24 and wall 22 obturate combustion gases in a manner which will be set forth in greater detail hereinafter. The legs 16 serve to firmly interconnect opposite peripheral parts of the transverse walls 12 and 22 and maintain the walls 12 and 22 in coaxial relationship with one another, thus tilting of the projectile cup 4 with respect to the obturator 8 is prevented by the legs 16. Furthermore, the coaxial relationship is maintained during axial compression of the legs 16 because the legs 16 connect opposite peripheral portions of the projectile cup 4 and obturator 8 rather than opposite internal portions thereof.

Referring now to FIG. 4, the wad structure 2 is shown loaded in a shotshell. The shotshell includes a tubular side wall 26 of paper, plastic, or the like on which is mounted a metallic head element 28. A base wad 30 of paper, plastic, or the like is positioned in the shell tube 26, the wad 30 being operative to secure a primer member 32 in place. A propellant charge 34 is positioned above the primer member 32, and the obturating portion 8 of the wad 2 overlies the propellant charge 34. A column of shot pellets 36 is positioned in the projectile pocket 4 and a deflectable card wad 38 overlies the shot column 36 and closes off the top of the shotshell. Alternatively, the shotshell may have its top part closed off in any conventional manner so, for example, by inwardly folding the top part of the shell tube 26.

Referring now to FIGS. and 6, the shotshell is shown chambered in a firearm and fired therein. The firearm includes a barrel member 40 (shown fragmentarily) having a bore 42 which opens into a firing chamber 44 at the rear of the barrel 40. It is noted that the outside surface of the shell tube 26 is fully supported by the wall of the barrel bore 42 and firing chamber 44, and thus reinforced thereby. The bolt assembly of the gun is indicated schematically by the numeral 46. When the shell is fired the propellant is consumed to to produce high pressure combustion gases which act upon the wall 22 and skirt 24 and cause the latter to flare outwardly into sealing engagement with the inner surface of the shell tube 26. Thus the wad structure 2 and shot column 36 are propelled along with the card wad 38 out of the shell tube. Since the shot column 36 initially resists forward movement, the pressurized gas and shot column 36 combine to compress the cushioning portion 6 of the wad structure. Thus the legs 16 are axially compressed and their hinges 18 cause the compressed legs 16 to flex outwardly, or in other words, cause the cushioning portion 6 to enlarge radially. However, the shell tube 26 and gun chamber 44 resist the outward flexure of each of the legs l6 equally, thus preventing complete collapse of the cushioning portion 6 and controlling the degree of collapse which does occur. Furthermore, the outward flexure of the legs 16 tends to transmit the compressive forces derived from the expanding combustion gases outwardly against the shell tube 26 and chamber wall 44 instead of transmitting the forces entirely against the shot column 36 as do rigid cushioning portions. Thus the shot column 36 tends to retain it cylindrical configuration rather than becoming disrupted by the forces generated by the expanding combustion gases. Retention of the cylindrical configuration of the shot column improves shot patterns by keeping the shot pellets as closely grouped together as possible while they are in the shot pocket. It is further noted that as the compressive forces generated by the combustion gases increase, the bearing surface on the shell tube 26 and barrel bore 42 will increase in area as a greater portion of each leg 16 is forced outwardly thereagainst, thus absorbing more of the compressive force and increasing resistance to collapse of the cushioning portion 6 of the wad structure 2.

Referring now to FIG. 6, the wad structure 2 is shown after it has moved free of the shell tube and as it continues through the barrel bore 42. The flexible skirt 24 flares outwardly into sealing engagement with the wall of the barrel bore 42 and compression of the cushioning or filler portion 6 of the wad causes the legs 16 to expand or flex outwardly against the wall of the barrel bore 42. The circumferential peripheral support of the projectile cup 4 afforded by the legs 16 keeps the projectile cup 4 and shot column 36 coaxial with the barrel bore 42 and resists tilting of the shot column 36 with respect to the barrel bore axis. The wall of the barrel bore 42 continues to absorb a large amount of the force compressing the cushioning portion 6 of the wad, and continues to resist complete collapse of the cushioning portion 6, thus providing controlled cushioning of the shot column 36 from the time the shell is fired until the wad exits from the gun muzzle.

Tests of the wad structure of this invention have established shot patterns of 83.5 percent of the shot charge in a thirty inch circle at forty yards, as compared to 80.7 percent patterns with a prior art unitary wad structure of the type disclosed in US. Pat. No. 3,285,174 referred to above, and 80.9 percent patterns with a prior art composite wad structure of the same general type shown in US. Pat. No. 3,270,669 referred to above. This improvement in patterns is of particular advantage in competitive shooting, such as long yardage handicap trap shooting.

Since many changes and variations of the disclosed embodiment of the invention may be made without departing from the inventive concept, it is not intended to limit the invention otherwise than as required by the appended claims.

What is claimed is:

1. A unitary structure for use as a cushioning wad component of a cartridge, said structure comprising:

a. a first transverse wall having a generally cylindrical side surface;

b. a second transverse wall having a generally cylindrical side surface, said second wall being substantially parallel to said first wall and substantially coaxial therewith; and

c. a plurality of legs unitary with said first and second walls and interconnecting opposite peripheral portions of said first and second walls to axially offset said first wall from said second wall, said legs providing a free space between opposed central portions of said walls, each of said legs having a radially outer side surface which is substantially coextensive with said cylindrical side surfaces of said walls, and each of said legs being provided with means for imparting radially outward flexure to said legs to provide controlled axial collapse of said structure when the latter is housed in a tubular casing and subjected to opposed axial compressive forces.

2. The structure of claim 1, wherein each of said legs includes a hinge to promote said radially outward flexure of said legs.

3. The structure of claim 1, further comprising cylindrical'means unitary with one of said walls to provide a projectile-receiving cup having an open mouth end and an opposite end closed by said one wall.

4. A unitary structure for use as a cushioning wad component of a cartridge, said structure comprising:

a. first and second transverse walls substantially parallel to each other and spaced apart along a common axis, each of said walls having a generally cylindrical side surface; and

at least three separate and distinct legs unitary with said first and second walls and interconnecting opposite peripheral portions of said first and second walls, with non-peripheral portions of said first and second walls being unconnected, each of said legs including means for causing radially outward flexure of said legs to occur when said structure is subjected to opposed axial compressive forces, and each of said legs having an outer side surface which is substantially coextensive with said cylindrical side surfaces of said first and second walls.

5. The structure of claim 4, wherein said legs are angularly spaced apart from each other at substantially equal intervals about the axis of said structure.

6. The structure of claim 4, wherein each of said legs includes a hinge to cause said radially outward'flexure.

7. A cartridge having a tubular side wall member with a basal end which is closed and which includes a primer member, a charge of propellant material in said tubular member adjacent said primer member, a filler and cushioning wad member comprising:

a. a first vtransverse wall overlying said propellant material, said first wall having a side surface closely confined by said cartridge tubular side wall;

b. a second transverse wall offset from said first wall and having a side surface closely confined by said cartridge tubular side wall;

. a plurality of separate and distinct legs unitary with said first and second walls, said legs being operative to interconnect opposed peripheral portions of said first and second walls, with non-peripheral portions of said first and second walls being unconnected, each of said legs including means to permit radially outward flexure of said legs to occur when said structure is subjected to opposite axial compressive forces, and each of said legs having an outer wall portion which is closely confined by said cartridge tubular side wall, with said tubular side wall being operative to increasingly resist outward flexure of said legs to progressively control the degree of movement of said first wall toward said second wall.

8. A unitary structure for use as a cushioning wad component of a cartridge, said structure comprising:

a. a pair of spaced apart transverse wall members having side surfaces of cylindrical configuration;

and a plurality of circumferentially spaced, axially extending support members unitary with said wall members to connect opposite peripheral portions of said wall members, each of said support mem bers having an outer wall, the entire extent of which is substantially coextensive with said cylindrical side surfaces of said transverse walls, and each of said support members having an inner wall portion including hinge means to cause each of said support members to flex radially outwardly when opposite axially directed forces are applied to said wall members.

9. The structure of claim 8, wherein said support members are three in number and are arranged at equal intervals about the circumference of said structure.

10. A unitary structure for use as a cushioning wad component of a cartridge, said structure comprising:

a. first and second walls spaced apart and extending transversely of said structure, said walls being parallel to each other and of circular configuration so as to each include a cylindrical side surface; and

b. a plurality of separate and distinct legs unitary with said first and second walls to interconnect the two, each of said legs having an arcuate outer surface which throughout its entire length is substantially coextensive with said cylindrical side surfaces of said first andsecond walls, and each of said legs having an inner surface which is dished out to weaken each leg and cause the latter to bend outwardly when opposite compressive forces are applied to said first and second walls.

t i i i 

1. A unitary structure for use as a cushioning wad component of a cartridge, said structure comprising: a. a first transverse wall having a generally cylindrical side surface; b. a second transverse wall having a generally cylindrical side surface, said second wall being substantially parallel to said first wall and substantially coaxial therewith; and c. a plurality of legs unitary with said first and second walls and interconnecting opposite peripheral portions of said first and second walls to axially offset said first wall from said second wall, said legs providing a free space between opposed central portions of said walls, each of said legs having a radially outer side surface which is substantially coextensive with said cylindrical side surfaces of said walls, and each of said legs being provided with means for imparting radially outward flexure to said legs to provide controlled axial collapse of said structure when the latter is housed in a tubular casing and subjected to opposed axial compressive forces.
 1. A unitary structure for use as a cushioning wad component of a cartridge, said structure comprising: a. a first transverse wall having a generally cylindrical side surface; b. a second transverse wall having a generally cylindrical side surface, said second wall being substantially parallel to said first wall and substantially coaxial therewith; and c. a plurality of legs unitary with said first and second walls and interconnecting opposite peripheral portions of said first and second walls to axially offset said first wall from said second wall, said legs providing a free space between opposed central portions of said walls, each of said legs having a radially outer side surface which is substantially coextensive with said cylindrical side surfaces of said walls, and each of said legs being provided with means for imparting radially outward flexure to said legs to provide controlled axial collapse of said structure when the latter is housed in a tubular casing and subjected to opposed axial compressive forces.
 2. The structure of claim 1, wherein each of said legs includes a hinge to promote said radially outward flexure of said legs.
 3. The structure of claim 1, further comprising cylindrical means unitary with one of said walls to provide a projectile-receiving cup having an open mouth end and an opposite end closed by said one wall.
 4. A unitary structure for use as a cushioning wad component of a cartridge, said structure comprising: a. first and second transverse walls substantially parallel to each other and spaced apart along a common axis, each of said walls having a generally cylindrical side surface; and b. at least three separate and distInct legs unitary with said first and second walls and interconnecting opposite peripheral portions of said first and second walls, with non-peripheral portions of said first and second walls being unconnected, each of said legs including means for causing radially outward flexure of said legs to occur when said structure is subjected to opposed axial compressive forces, and each of said legs having an outer side surface which is substantially coextensive with said cylindrical side surfaces of said first and second walls.
 5. The structure of claim 4, wherein said legs are angularly spaced apart from each other at substantially equal intervals about the axis of said structure.
 6. The structure of claim 4, wherein each of said legs includes a hinge to cause said radially outward flexure.
 7. A cartridge having a tubular side wall member with a basal end which is closed and which includes a primer member, a charge of propellant material in said tubular member adjacent said primer member, a filler and cushioning wad member comprising: a. a first transverse wall overlying said propellant material, said first wall having a side surface closely confined by said cartridge tubular side wall; b. a second transverse wall offset from said first wall and having a side surface closely confined by said cartridge tubular side wall; c. a plurality of separate and distinct legs unitary with said first and second walls, said legs being operative to interconnect opposed peripheral portions of said first and second walls, with non-peripheral portions of said first and second walls being unconnected, each of said legs including means to permit radially outward flexure of said legs to occur when said structure is subjected to opposite axial compressive forces, and each of said legs having an outer wall portion which is closely confined by said cartridge tubular side wall, with said tubular side wall being operative to increasingly resist outward flexure of said legs to progressively control the degree of movement of said first wall toward said second wall.
 8. A unitary structure for use as a cushioning wad component of a cartridge, said structure comprising: a. a pair of spaced apart transverse wall members having side surfaces of cylindrical configuration; and b. a plurality of circumferentially spaced, axially extending support members unitary with said wall members to connect opposite peripheral portions of said wall members, each of said support members having an outer wall, the entire extent of which is substantially coextensive with said cylindrical side surfaces of said transverse walls, and each of said support members having an inner wall portion including hinge means to cause each of said support members to flex radially outwardly when opposite axially directed forces are applied to said wall members.
 9. The structure of claim 8, wherein said support members are three in number and are arranged at equal intervals about the circumference of said structure. 